Tension mechanism for testing-machines.



H; L. SCOTT. TENSION MECHANISM FOR TESTING MACHINES.

APPLICATION FILED JULY 6,1915. 1,21 9,594. Patented Mar. 20, 1917.

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TENSlON MECHANISM FOR TESTING MACHINES. APPHCATION FILED IULY 6,1915

1,21 9,594. Patented Mar. 20, 191:.

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HENRY L. SCOTT,

0F PROVIDENCE, RHODE ISLAND.

TENSION MECHANISM FOR TESTING-MACHINES.

m Specification of Letters Patent.

Patented Mar. 20, 191i 7.

Application filed July 6, 1915. Serial No. 38,071.

To all whom it may concern:

ments in Tension Mechanism for Testingachines, of which the following is a specification.

This invention relates to tension applying mechanism more particularly adapted for use on testing machines, and the object of this invention is to provide a device of this character that is positive in its tension operation and one whose feeding action ma be either manually or automatically re versed.

A further object of this invention is to provide means whereby the tension will antomatically stop when it has returned to the starting point after an operating stroke.

object of the invention is to provide means whereby the return stroke will be accelerated over the tension stroke.

A still further object of the invention is that the tension stroke of the mechanism will be operated in a positive manner through a toothed clutch and the return stroke through a friction clutch.

With these and other objects in view, the invention consists of certain novel features of construction, as will be more fully described, and particularly pointed out in the appended claims.

In the accompanying drawings: 7

Fig. 1* is a side elevation showing a hori- Zontal type of testing machine to which my improved tension operating mechanism is attached.

Fig. 2- is a plan view of the tension operating mechanism with the top of its inclosing casing removed.

Fig. 3- is a plan view of the casing showing a portion of the operating mechanism removed therefrom to better illustrate a portion of the shifting mechanism.

Fig. lis a sectional end View on line H of Fig. 2 illustrating the general arrangement of the gearing whereby the return movement of the screw is accelerated.

Fig. 5 is a detail elevation of the positive and friction clutches also the yoke and yoke bar for shifting the clutches.

*ig. 6- is a plan view showing a. detail of the yoke bar and the two notches to be engaged by the yoke'lever.

the machine, which frames are connected by the tie rods 12 and 13. Carriages 14 and 15 are mounted to roll on rails 16. On carriage 4 is mounted the clamp 17 and on carriage 15 the clamp 18, between which clamps the material a to be tested is gripped. The cari is connected through the chain 19 means to the pointer 21, whereby the tension on the goods being tested is indicated by the position of the pointer on the graduated dial 22. The tension carriage 15 is connected by the non-rotatable endwise movable screw 23 to the tension mechanism, presently described, located in the casing 24 on the frame 10 through which casing this screw passes as shown in Fig. 2.

In order that the endwise movement of this screw may be effected without rotating the same, I have mounted thereon a nut 25, which serves as a bushing to the two driving gears 26 and 27 and to reduce the friction of the thrust or working strain on this screw, I have interposed a ball thrust bearing 28 between the nut 25 and bearing 29.

In order to facilitate the operation of a machine of this character, it is found advisable to provide means whereby the return stroke may be accelerated over that of the working stroke. Therefore to accomplish this, I have madethese two gears of different sizes and have arranged to drive them through different sets of mechanism presently described.

Power may be applied to this tension mechanism either by a hand wheel 30 or through tight and loose pulleys 31 to the employed for driving shaft 32 on which shaft is mounted the double clutch member 33 to slide on the usual feather key 52L, see Fig. 5. One end of this clutch member is provided with teeth 35 adapted to engage and positively drive the other member of the clutch 36, which second member is loosely mounted on its shaft and to which is connected a bevel gear 37 n1 'ch meshes with a similar gear 38 keyed to the shaft 39. ()n the outer portion of this shaft is mounted a small gear 7L0 adapted to mesh with the large gem- 27, whereby when the toothed clutch is thrown. into cn agement the nut is turned by the large gear to draw the screw outward or to impart to the screw its working stroke. On the opposite end of this clutch member is a cone member 41 which is adapted to engage its corresponding clutch member 4:2. To this latter member as shown in Fig. 2 is connected a bevel gear 4-3 which meshes with the pinion 1:1 mounted on the shaft if) to which shaft is also connected a large gear 1'16 which meshes with the nut gear so, whereby when the cone clutch is in engagement, the nut is driven at a relatively fast speed to return the screw and its clamp to the starting position. It is found in practice that owing to the great st positive or toothed shaped clutch is necessary for driving the screw on its operating stroke, but as the work of driving this screw upon its return stroke is very much less than on its operating stroke I have provided a cone shaped clutch l-O and ll through which this reverse action is imparted.

A further object and essential feature of the cone clutch is that after the tension mechanism is returned to normal the members of the cone clutch are automatically withdrawn from each other requiring but a, slight movement to release and free itself and when so released the parts continue to rotate one within the other noisclessly and vithout the clicking sound of ratchet teeth which is the case when a toothed clutch is this particular purpose.

This is quite essential as these machines are often employed in business offices where silent running is demanded.

It is found in practice advisable to provide means whereby this mechanism may be automatically operated to shift the clutches when the carriage reaches a predetermined point in its travel during its working stroke, and to return the carriage to its starting point without attention from the operator. To accomplish this, I have provided a yoke member n to engage the clutch member 33 and have connected this yoke to the endwise movable yoke bar 118 which receives its bearing in bosses a9 and 50 am upon the screw that a in the casing. A spring 51, see Fig. 3, exerts a i? tension on this bar to move the clutch into reverse position when released and a latch lever pivoted at 53 and under tension of spring to is provided with a lip 5st for engaging a notch 55 in this yoke bar to normally hold the same against movement under action of its spring 51. This latch lever 52 has an outwardly extending arm 57. l have also provided a bell crank lever 58 pivoted at (30, one arm of which engages an abutment Til on the yoke bar as and the other arm (31 of this lever is provided with an opening 62. In order to operate this mechanism in the casing from any desired point along the machine, I have provided an elongated rod 3 which extends along the top of the frame. its inner end (it passes through the opei'iing 62 in the arm 61 and abuts against the end 57 of the latch lever 52. On this rod as illustrated in Fig. 1, l have located dogs (35 and (36 which are adapted to be engaged by the car 67 on the carriage 15, and l have also provided collars GS and (39 on this rod which are engaged by the arm 70 of the hand lever 71., which is pivoted to tl e frame at 72. Assuming now that the mechanism is in neutral position which is that illustrated in Fig.2 and the sample a to be tested is positioned between the clamps 17 and 18. To start the testing operation, I move the handle of the lever 71 downward which draws the rod 63 outward causii'ig the arm 58 of the bell crank lever to move the yoke 47 and throw the positive or toothed clutch into engagement to drive the nut 25 through the gears 40 and 27 to slowly but powerfully draw the tension screw outward. Now as the carriage 15 moves to the right and as soon as it has completed its testing stroke, it engages the dog 65, presses the rod 63 inward causing its end (i-al to press against the end :17 of the latch lever 52 withdrawing it from notch and permitting the yoke at? under tension of the spring pressed yoke bar to disengage the teeth of the positive clutch and move the cone 41 into engagement with its member 12, whereby a much quicker motion is imparted to the screw by means of the differently proportioned gearing, to return the tension elements to the starting point at which time the car (37 on the carriage 15 engages the dog 6%, draws the rod 63 outward and the clutch member 41 out of engagement with this iember 42 snliiciently to permit the mechanism to run idle until again manually operated.

In some cases particularly when this 'iechanism is applied to a vertical machine, it is found more convenient to do away with the lever 71 for operating the tensionmechanism and to provide a lever mounted on the casing, itself, in such ,a position as to be handy to operate. To accomplish this, I have provided a lever 72, see Fig. 1, pivoted at 73 on the casing and provided with an arm 74 which engages an endwise movable spindle 75. This spindle passes through the casing, see Fig. 3, and its inner end is provided with a slotted member 76 through which a pin 77 in the lever 61 extends, and a spring 7 8 presses against a portion 76 of the spindle to normally press it inward, which pressure serves to return the hand lever 72 back to normal as soon as released after performing this operation. In operating this lever when the mechanism is set in a vertical position, the handle is moved forward, which movement as will be seen by the mechanism in Fig. 3 and as above described operates through the yoke to cause the positive clutch members to move the screw through its working stroke, and when the screw is moved a predetermined distance the mechanism is stopped through a movement of the rod 63.

It is found in practice desirable in some cases to provide means whereby instead of permitting the automatic shift to reverse the action of the machine entirely, to provide means whereby this automatic operation simply stops the machine on its outer stroke as well as on its inward stroke. To accomplish this as illustrated in Fig. 6 a second notch 90 is provided in the bar 48, whereby when the latch 54 is withdrawn from notch 55, it simply permits the yoke bar to move a sufiicient distance to disengage the positive clutch when this latch engages the boss 90 and retains the clutch in neutral position.

In some cases instead of operating through the two bell crank levers illustrated in Fig. 3, I use the construction illustrated in Fig. 7 whereby a wedge 80 is mounted on the endwise movable rod 81 which wedge engages the lever 82 to directly act upon and throw the clutch member 83. In this mechanism when it is desired to start the machine the hand lever 84 is moved into engagement where it is held by the member 85 resting in the notch 86, then as the screw 87 moves inward the arm 88 engages the collar 89 and moves the wedge inward causing the clutch member 83 to move in the opposite direction under tension of the spring, not shown, to

reverse the action of the mechanism.

This invention is not restricted to any of the particular forms of mechanism herein illustrated and described as various modifications may be made without departing from the spirit and scope thereof.

I claim:

'1. In a testing machine, means for gripping the work, a screw connected to the grip per, means operating on the screw for moving the gripper to tension the goods, means for automatically reversing the action of the screw at a predetermined point in the tension stroke, said reversing means being adapted to produce more rapid motion in the reverse than in the direct movement of the screw.

2. In a testing machine, means for gripping the work, a screw connected tothe gripper, means operating on the screw for feeding the gripper to tension the goods, and manually operable means for starting and stopping and reversing the action of the screw, and means including differential gearing for automatically returning said operable means to normal after an operating movement of the machine.

3. In a testing machine, a tension applying mechanism comprising means for gripping the work, a screw connected to the gripper, means operating on the screw for imparting a feeding movement to the gripper to tension the goods, means for automatically reversing the action of the screw at a predetermined point in the tension stroke, said reversing means being adapted to produce more rapid motion in the reverse than in the direct movement of the screws.

I. In a testing machine, a tension applying mechanism comprising means for gripping the work, a screw connected to the gripper, means operating on the screw for imparting an endwise feeding movement to the gripper to tension the goods, means for automatically reversing the action of the screw at a predetermined point in the tension stroke, and means for automatically stopping the movement of the gripper at the end of its return stroke.

5. In a testing machine, a tension applying mechanism comprising means for gripping the work, a screw connected to the gripper, means operating on the screw for imparting a feeding movement to the grip-- per to tension the goods and means for reversing the action of the screw at a pre determined point in the movement of the gripper, said reversing means being adapted to produce more rapid motion in the reverse than in the direct movement of the screw, and means for stopping the gripper at the end of its return stroke.

6. In a testing machine, means for gripping the work to be tested, a screw connected to drive the gripper, means operated by the screw for feeding the gripper to tension the goods, a manually operable shipper lever for starting the machine and means for automatically returning said lever to normal after an operating movement of the machine.

7. In a testing machine, means for gripping the work to be tested, a screw operatively connected to the gripper, means ineluding a toothed clutch for positively operating upon the screw to feed the gripper in one direction, and a friction clutch for opcrating the reverse mechanism.

8. In a testing machine, means for gripping the work to be tested a screw operatively connected to the gripper, a rotatable nut on the screw for drawing the nut in one direction and a friction clutch for reversing the action of the nut and screw. 10

In testimony whereof I afiix my signature.

:HENRY L. SCOTT.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, I). C. 

